It is known that sleeves for neck rests serve for receiving neck rest bars of a neck rest which is attached to seat backs of automobile seats. The sleeves for neck rests are usually provided with means to lock the neck rest bars at different levels. Further, means are provided to eliminate the locked position. The neck rest bars have am integrally formed neck rest body which is composed of an elongate sleeve portion and an upper radial flange portion which comes to bear against the upper side of the seat back when the sleeve for the neck rest is introduced into the seat back. The flange portion frequently has mounted therein a spring which cooperates with catch recesses of the neck rest bars in order to lock them.
The sleeve for the neck rest, in turn, is received in a respective receptacle in the seat back. The receptacle can consist of a tubular piece which is inserted into the seat back. Alternatively, other receptacle constructions may be provided which receive the sleeve for the neck rest.
Both the interior of the sleeve for the neck rest and the outer contour are subjected to tolerances. The neck rest bars and the receptacles in the backs of the seats also feature tolerances. Therefore, care should be taken to provide for an adequate tolerance compensation. In this context, it is known to form a resilient portion integrally with the neck rest body that extends into the interior of the sleeve for the neck rest if a neck rest bar is not introduced. If the bar is introduced the resilient portion will be deformed outwardly and applies a respective pressure to the neck rest bar. As a result, a tolerance compensation is obtained in the interior of the sleeve for the neck rest. Similarly, known sleeves for neck rests provide at least one outer resilient portion which cooperates with the neck rest receptacle when the sleeve for the neck rest is introduced into the receptacle. The disadvantage of such resilient portions is that they gradually lose their resilience property, particularly during temperature variations. The same is the case when ribs or similar protrusions are provided which radially extend into the sleeve for the neck rest or project from their outer side and are supposed to ensure a tolerance compensation. Such protrusions will flow away at higher temperatures and backlash-free tuning is no longer possible.
It is further known to mount metallic springs on the neck rest body which cooperate with the neck rest bar or neck rest receptacle. The disadvantage of metallic springs is that they involve efforts in manufacture and develop noise when in use.